Maize is cultivated throughout the world; a greater weight of maize is produced each year than any other grain. In 2020, world production was 1.1 billion tonnes. It is afflicted by manypests anddiseases; two majorinsect pests,European corn borer andcorn rootworms, have each caused annual losses of a billion dollars in the US. Modernplant breeding has greatly increased output and qualities such as nutrition, drought tolerance, and tolerance of pests and diseases. Much maize is nowgenetically modified.
Maizerequires human intervention for its propagation. The kernels of its naturally-propagatingteosinte ancestor fall off the cob on their own, while those ofdomesticated maize do not.[2] All maize arose from a single domestication in southern Mexico about 9,000 years ago. The oldest surviving maize types are those of the Mexican highlands. Maize spread from this region to the lowlands and over the Americas along two major paths.[3] The centre of domestication was most likely theBalsas River valley of south-central Mexico.[4] Maize reached highland Ecuador at least 8000 years ago.[5] It reached lower Central America by 7600 years ago, and the valleys of the ColombianAndes between 7000 and 6000 years ago.[4]
The earliest maize plants grew a single, small ear per plant.[6] TheOlmec andMaya cultivated maize in numerous varieties throughoutMesoamerica; they cooked, ground and processed it throughnixtamalization.[7] By 3000 years ago, maize was central to Olmec culture, including their calendar, language, and myths.[8]
Cultivation of maize, in an illustration from the 16th c.Florentine Codex
After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traderscarried it back to Europe. Spanish settlers much preferredwheat bread to maize. Maize flour could not be substituted for wheat for communion bread, since inChristian belief at that time only wheat could undergotransubstantiation and be transformed into the body of Christ.[11]
Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere.[11] By the 17th century, it was a common peasant food in Southern Europe. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially aspolenta in Italy.[12]
When maize was introduced into Western farming systems, it was welcomed for its productivity. However, a widespread problem of malnutrition soon arose wherever it had become astaple food.[13] Indigenous Americans had learned to soak maize inalkali-water — made with ashes andlime — since at least 1200–1500 BC, creating the process of nixtamalization. They did this to liberate the corn hulls, but coincidentally it also liberated the B-vitaminniacin, the lack of which causedpellagra.[14] Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high-lysine maize and the promotion of a more balanced diet have contributed to its demise. Pellagra still exists in food-poor areas and refugee camps where people survive on donated maize.[15]
Names
The namemaize derives from the Spanish formmaíz of theTaínomahis.[16] The Swedish botanistCarl Linnaeus used the common name maize as the species epithet inZea mays.[17] The namemaize is preferred in formal, scientific, and international usage as acommon name because it refers specifically to this one grain, unlikecorn, which has a complex variety of meanings that vary by context and geographic region.[18] Most countries primarily use the termmaize, and the namecorn is used mainly in the United States and a handful of other English-speaking countries.[19][20] In countries that primarily use the termmaize, the wordcorn may denote anycereal crop, varying geographically with the localstaple,[21] such as wheat in England and oats in Scotland or Ireland.[18] The usage ofcorn for maize started as a shortening of "Indian corn" in 18th-century North America.[22]
The historian of food Betty Fussell writes in an article on the history of the wordcorn in North America that "[t]o say the wordcorn is to plunge into the tragi-farcical mistranslations of language and history".[8] Similar to the British usage, the Spanish referred to maize aspanizo, a generic term for cereal grains, as did Italians with the termpolenta. The British later referred to maize as Turkey wheat, Turkey corn, or Indian corn; Fussell comments that "they meant not a place but a condition, a savage rather than a civilized grain".[8]
Maize is a tallannual grass with a single stem, ranging in height from 1.2 m (4 ft) to 4 m (13 ft).[31] The long narrow leaves arise from thenodes or joints, alternately on opposite sides on the stalk.[31] Maize ismonoecious, with separate male and female flowers on the same plant.[31] At the top of the stem is the tassel, aninflorescence of male flowers; their anthers release pollen, which isdispersed by wind.[31] Like other pollen, it is anallergen, but most of it falls within a few meters of the tassel and the risk is largely restricted to farm workers.[32]The female inflorescence, some way down the stem from the tassel, is first seen as a silk, a bundle of softtubular hairs, one for thecarpel in each female flower, which develops into a kernel (often called a seed. Botanically, as in all grasses, it is a fruit, fused with the seed coat to form acaryopsis[33]) when it is pollinated.[31] A whole female inflorescence develops into an ear orcorncob, enveloped by multiple leafy layers or husks.[31] Theear leaf is the leaf most closely associated with a particular developing ear. This leaf and those above it contribute over three quarters of the carbohydrate (starch) that fills the grain.[34]
The grains are usually yellow or white in modern varieties; other varieties have orange, red, brown,blue,purple, or black grains. They are arranged in 8 to 32 rows around the cob; there can be up to 1200 grains on a large cob.[6] Yellow maizes derive their color fromcarotenoids; red maizes are colored byanthocyanins andphlobaphenes; and orange and green varieties may contain combinations of these pigments.[35]
Maize has short-dayphotoperiodism, meaning that it requires nights of a certain length to flower. Flowering further requiresenough warm days above 10 °C (50 °F). The control of flowering is set genetically; the physiological mechanism involves thephytochrome system. Tropical cultivars can be problematic if grown in higher latitudes, as the longer days can make the plants grow tall instead of setting seed before winter comes. On the other hand, growing tall rapidly could be convenient for producing biofuel.[31]
Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), which provides a measure of protection against a wide range of pests.[36] Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to being uprooted by severe winds.[37]
Many small male flowers make up the male inflorescence or tassel.
The Maize Genetics and Genomics Database is funded by theUS Department of Agriculture to support maize research.[42] TheInternational Maize and Wheat Improvement Center maintains a large collection of maize accessions tested and cataloged for insect resistance.[43] In 2005, the USNational Science Foundation, Department of Agriculture, and theDepartment of Energy formed a consortium to sequence the maizegenome. The resultingDNA sequence data was deposited immediately intoGenBank, a public repository for genome-sequence data.[44] Sequencing of the maize genome was completed in 2008.[45] In 2009, the consortium published results of its sequencing effort.[46] The genome, 85% of which is composed oftransposons, contains 32,540 genes. Much of it has been duplicated and reshuffled byhelitrons, a group oftransposable elements within maize's DNA.[47]
Breeding
Conventional breeding
Maize breeding in prehistory resulted in large plants producing large ears. Modernbreeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful, developing Reid's Yellow Dent in the 1860s. These early efforts were based onmass selection (a row of plants is grown from seeds of one parent), and the choosing of plants after pollination (which means that only the female parents are known). Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selectedinbred lines (G. H. Shull, 1909), and the highly successfuldouble cross hybrids using four inbred lines (D. F. Jones c. 1918, 1922). University-supported breeding programs were especially important in developing and introducing modern hybrids.[48]
Since the 1940s, the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic engineering have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant.[49]
Certain varieties of maize have been bred to produce many ears; these are the source of the "baby corn" used as a vegetable inAsian cuisine.[50][51] A fast-flowering variety named mini-maize was developed to aid scientific research, as multiple generations can be obtained in a single year.[52] One strain called olotón has evolved a symbiotic relationship withnitrogen-fixing microbes, which provides the plant with 29%–82% of its nitrogen.[53] TheInternational Maize and Wheat Improvement Center (CIMMYT) operates a conventional breeding program to provide optimized strains. The program began in the 1980s.[54] Hybrid seeds are distributed in Africa by its Drought Tolerant Maize for Africa project.[55]
Genetically modified maize was one of the 26genetically engineered food crops grown commercially in 2016.[58][59] The vast majority of this isBt maize. Genetically modified maize has been grown since 1997 in the United States and Canada;[60] by 2016, 92% of the US maize crop was genetically modified.[58] As of 2011, herbicide-tolerant maize and insect-resistant maize varieties were each grown in over 20 countries.[61]In September 2000, up to $50 million worth of food products were recalled due to the presence ofStarlink genetically modified corn, which had been approved only for animal consumption.[62]
Origin
External phylogeny
The maizegenusZea is relatively closely related tosorghum, both being in thePACMAD clade of Old World grasses, and much more distantly torice andwheat, which are in the other major group of grasses, theBOP clade. It is closely related toTripsacum, gamagrass.[63]
Maize is thedomesticated variant of the four species ofteosintes, which are itscrop wild relatives.[64] The teosinte origin theory was proposed by the Russian botanistNikolai Ivanovich Vavilov in 1931, and the AmericanNobel Prize-winnerGeorge Beadle in 1932.[65]: 10 The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (gt1,A0A317YEZ1) and teosinte branched-1 (tb1,Q93WI2).[64] In the late 1930s,Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species ofTripsacum, a related genus; this has been refuted by moderngenetic testing.[65]
In 2004,John Doebley identified Balsas teosinte,Zea mays subsp.parviglumis, native to theBalsas River valley in Mexico's southwestern highlands, as thecrop wild relative genetically most similar to modern maize.[66][67] The middle part of the short Balsas River valley is the likely location of early domestication. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far fromIguala, Guerrero.[68] Doebley and colleagues showed in 2002 that maize had been domesticated only once, about 9,000 years ago, and then spread throughout the Americas.[3]
Maize pollen dated to 7,300 years ago fromSan Andres, Tabasco has been found on the Caribbean coast.[68] A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found atGuila Naquitz Cave in theOaxaca Valley, are roughly 6,250 years old; the oldest ears from caves nearTehuacan, Puebla, are 5,450 years old.[7]
Spreading to the north
Around 4,500 years ago, maize began to spread to the north. In the United States, maize was first cultivated at several sites in New Mexico and Arizona about 4,100 years ago.[7] During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for the new crop.[69] The rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwatermussels, which are very sensitive to environmental changes.[70]
Agronomy
Growing
Because it is cold-intolerant, in thetemperate zones maize must be planted in the spring. Itsroot system is generally shallow, so the plant is dependent on soil moisture. As a plant that usesC4 carbon fixation, maize is a considerably more water-efficient crop than plants that useC3 carbon fixation such asalfalfa andsoybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by theFourth of July", although modernhybrids generally exceed this growth rate. Maize used forsilage is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of Africa, where periodicdrought regularly causes maize crop failure and consequentfamine. Although it is grown mainly in wet, hot climates, it can thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop.[71]
Maize was planted by theNative Americans in small hills of soil, in thepolyculture system called theThree Sisters.[72] Maize provided support forbeans; the beans provided nitrogen derived from nitrogen-fixingrhizobia bacteria which live on the roots of beans and otherlegumes; andsquashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil.[73]
Seedlings three weeks after sowing
Young stalks
Mature plants showing ears
Harvesting
Sweet corn, harvested earlier than maize grown for grain, grows to maturity in a period of from 60 to 100 days according to variety. An extended sweet corn harvest, picked at the milk stage, can be arranged either by plantinga selection of varieties that ripen earlier and later, or by planting different areas at fortnightly intervals.[74]Maize harvested as a grain crop can be kept in the field a relatively long time, even months, after the crop is ready to harvest; it can be harvested and stored in the husk leaves if kept dry.[75]
According to the U.S. Department of Agriculture, in the four decades from 1855 to 1894 the amount of labor required to produce one bushel of maize declined from four hours and thirty four minutes to only forty-one minutes.[76] Before 1940, most maize in North America was harvested by hand. This involved a large number of workers and associated social events (husking or shuckingbees). From the 1850s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving thestover) and corn binders, which arereaper-binders designed specifically for maize. The latter producesheaves that can beshocked. By hand or mechanical picker, the entire ear is harvested, which requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored incorn cribs, sufficient for some livestock feeding uses. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with acombine harvester and store it inbins. The combine with a corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to becomeorganic matter for thesoil. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates the husk and the cob, keeping only the kernels.[77]
Drying is vital to prevent or at least reduce damage bymould fungi, which contaminate the grain withmycotoxins.Aspergillus andFusarium spp. are the most common mycotoxin sources, and accordingly important in agriculture.[60] If the moisture content of the harvested grain is too high,grain dryers are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases (propane ornatural gas) and electricity to power the blowers.[78]
Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain.[79] In 2020, total world production was 1.16 billiontonnes, led by the United States with 31.0% of the total (table). China produced 22.4% of the global total.[80]
Nematodes too are pests of maize. It is likely that every maize plant harbors some nematodeparasites, and populations ofPratylenchus lesion nematodes in the roots can be "enormous". The effects on the plants include stunting, sometimes of whole fields, sometimes in patches, especially when there is also water stress and poor control of weeds.[96]
Many plants, bothmonocots (grasses) such asEchinochloa crus-galli (barnyard grass) anddicots (forbs) such asChenopodium andAmaranthus may compete with maize and reduce crop yields. Control may involve mechanical weed removal, flame weeding, or herbicides.[97]
In prehistoric times, Mesoamerican women used ametate quern to grind maize into cornmeal. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally containsniacin, an important nutrient, it is notbioavailable without the process ofnixtamalization. The Maya used nixtamal meal to make porridges and tamales.[102] Maize is a staple ofMexican cuisine.Masa (nixtamal) is the main ingredient fortortillas,atole and many other dishes of Central American food. It is the main ingredient ofcorn tortilla,tamales,atole and the dishes based on these.[103]The corn smut fungus, known ashuitlacoche, which grows on maize, is a Mexican delicacy.[104]
Coarse maize meal is made into a thickporridge in many cultures: from thepolenta of Italy, theangu of Brazil, themămăligă of Romania, tocornmeal mush in the US (orhominygrits in the Southern US) or the food calledmieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop.[105]
Sweet corn, a genetic variety that is high in sugars and low in starch, is eaten in the unripe state ascorn on the cob.[106]
Poster of maize-based foods, US Food Administration, 1918
Maize is a major source ofanimal feed. As a grain crop, the driedkernels are used as feed. They are often kept on thecob for storage in acorn crib, or they may be shelled off for storage in agrain bin. When the grain is used for feed, the rest of the plant (thecorn stover) can be used later asfodder,bedding (litter), orsoil conditioner. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usuallychopped and made intosilage, as this is more digestible and more palatable to ruminants than the dried form.[111] Traditionally, maize was gathered intoshocks after harvesting, where it dried further. It could then be stored for months until fed to livestock. Silage can be made insilos or in silage wrappers. In the tropics, maize is harvested year-round and fed as green forage to the animals.[112]Baled cornstalks offer an alternative tohay foranimal feed, alongside directgrazing of maize grown for this purpose.[113]
Cattle wait alongside a fence as a truck distributes a grain feed composed of corn by-products into troughs.
Feed maize is being used for heating; specializedcorn stoves (similar towood stoves) use either feed maize or wood pellets to generate heat. Maize cobs can be used as abiomass fuel source. Home-heating furnaces which use maize kernels as a fuel have a large hopper that feeds the kernels into the fire.[116] Maize is used as a feedstock for the production ofethanol fuel.[117] The price of food is indirectly affected by the use of maize for biofuel production: use of maize for biofuel production increases the demand, and therefore the price of maize.[118] A pioneeringbiomass gasification power plant in Strem,Burgenland, Austria, started operating in 2005. It would be possible to creatediesel from the biogas by theFischer Tropsch method.[119]
Farm-based maize silagedigester nearNeumünster, Germany, 2007, using whole maize plants, not just the grain. The green tarpaulin top cover is held up by the biogas stored in the digester.
In human culture
In Mesoamerica, maize is seen as a vital force, deified as amaize god, usually female.[120] In the United States, maize ears are carved intocolumn capitals in theUnited States Capitol building.[121] TheCorn Palace in Mitchell, South Dakota, uses cobs and ears of colored maize to implement a mural design that is recycled annually.[122] The concreteField of Corn sculpture inDublin, Ohio depicts hundreds of ears of corn in a grassy field.[123] A maize stalk with two ripe ears is depicted on thereverse of the Croatian 1lipa coin, minted since 1993.[124]
Maize kernels have sometimes denotedcowardice, as maize is fed to chickens, which symbolise cowards. In the months before the1973 Chilean coup d'etat anti-Allende protestors threw maize at military barracks in a call to depose him.[125][126]
^abPiperno, Dolores R. (October 2011). "The Origins of Plant Cultivation and Domestication in the New World Tropics: Patterns, Process, and New Developments".Current Anthropology.52 (S4):S453 –S470.doi:10.1086/659998.S2CID83061925.Recent studies in the Central Balsas River Valley of Mexico, maize's postulated cradle of origin, document the presence of maize phytoliths and starch grains at 8700 BP, the earliest date recorded for the crop (Piperno et al. 2009; Ranere et al. 2009). A large corpus of data indicates that it was dispersed into lower Central America by 7600 BP and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP. Given the number of Cauca Valley, Colombia, sites that demonstrate early maize, it is likely that the inter-Andean valleys were a major dispersal route for the crop after it entered South America
^Pagán-Jiménez, Jaime R.; Guachamín-Tello, Ana M.; Romero-Bastidas, Martha E.; Constantine-Castro, Angelo R. (June 2016). "Late ninth millennium B.P. use ofZea mays L. at Cubilán area, highland Ecuador, revealed by ancient starches".Quaternary International.404:137–155.Bibcode:2016QuInt.404..137P.doi:10.1016/j.quaint.2015.08.025.
^abcRoney, John (Winter 2009). "The Beginnings of Maize Agriculture".Archaeology Southwest.23 (1): 4.
^abcFussell, Betty (1999). "Translating Maize into Corn: The Transformation of America's Native Grain".Social Research.66 (1):41–65.JSTOR40971301.GaleA54668866ProQuest209670587.To say the word "corn" is to plunge into the tragi-farcical mistranslations of language and history. If only the British had followed Columbus in phoneticizing the Taino word mahiz, which the Arawaks named their staple grain, we wouldn't be in the same linguistic pickle we're in today, where I have to explain to someone every year that when Biblical Ruth "stood in tears amid the alien corn" she was standing in a wheat field. But it was a near thing even with the Spaniards, when we read in Columbus' Journals that the grain "which the Indians called maiz... the Spanish called panizo.' The Spanish term was generic for the cereal grains they knew - wheat, millet, barley, oats - as was the Italian term polenta, from Latin pub. As was the English term "corn", which covered grains of all kinds, including grains of salt, as in "corned beef". French linguistic imperialism, by way of a Parisian botanist in 1536, provided the term Turcicum frumentum, which the British quickly translated into "Turkey wheat", "Turkey corn", and "Indian corn". By Turkey or Indian, they meant not a place but a condition, a savage rather than a civilized grain, with which the Turks concurred, calling it kukuruz, meaning barbaric.
^abEarle, Rebecca (2012).The Body of the Conquistador: Food, Race, and the Colonial Experience in Spanish America, 1492–1700.Cambridge University Press. pp. 17, 144, 151.
^abEnsminger, Audrey H. (1994).Foods and Nutrition Encyclopedia, 2nd ed.CRC Press. p. 479.ISBN978-0-8493-8980-1.The word "maize" is preferred in international usage because in many countries the term "corn", the name by which the plant is known in the United States, is synonymous with the leading cereal grain; thus, in England "corn" refers to wheat, and in Scotland and Ireland it refers to oats.
^McLellan Plaisted, Susan (2013). "Corn". In Smith, Andrew (ed.).The Oxford Encyclopedia of Food and Drink in America (2nd ed.). New York:Oxford University Press.ISBN978-0199739226. RetrievedFebruary 15, 2023.The use of the word "corn" for what is termed "maize" by most other countries is peculiar to the United States. Europeans who were accustomed to the names "wheat corn", "barley corn", and "rye corn" for other small-seeded cereal grains referred to the unique American grain maize as "Indian corn." The term was shortened to just "corn", which has become the American word for the plant of American genesis.
^Mencken, H. L. (1984).The American language : an inquiry into the development of English in the United States (4th ed.). New York:Alfred A. Knopf. p. 122.ISBN0394400755.Corn, in orthodox English, means grain for human consumption, especially wheat, e.g., the Corn Laws. The earliest settlers, following this usage, gave the name of Indian corn to what the Spaniards, following the Indians themselves, had called maiz. . . . But gradually the adjective fell off, and by the middle of the Eighteenth Century maize was simply called corn and grains in general were called breadstuffs. Thomas Hutchinson, discoursing to George III in 1774, used corn in this restricted sense speaking of "rye and corn mixed." "What corn?" asked George. "Indian corn," explained Hutchinson, "or as it is called in authors, maize."
^Rusike, Joseph; Donovan, Philip A (1995). "The maize seed industry in Zimbabwe".Development Southern Africa.12 (2):189–196.doi:10.1080/03768359508439804.ISSN0376-835X.
^Chatham, Laura A.; Paulsmeyer, Michael; Juvik, John A. (2019). "Prospects for economical natural colorants: insights from maize".Theoretical and Applied Genetics.132 (11):2927–2946, and Figure 1.doi:10.1007/s00122-019-03414-0.PMID31451836.S2CID201729476.
^Strable, Josh; Scanlon, Michael J. (2009). "Maize (Zea mays): A Model Organism for Basic and Applied Research in Plant Biology".Cold Spring Harbor Protocols.2009 (10): pdb.emo132.doi:10.1101/pdb.emo132.ISSN1940-3402.PMID20147033.
^Jugenheimer, Robert W. (1958). "Agricultural Development Paper #62".Hybrid Maize Breeding and Seed Production. Rome:Food and Agriculture Organization.
^Wu, Chi-Chih; Diggle, Pamela K.; Friedman, William E. (September 2011). "Female gametophyte development and double fertilization in Balsas teosinte,Zea mays subsp.parviglumis (Poaceae)".Sexual Plant Reproduction.24 (3):219–229.doi:10.1007/s00497-011-0164-1.PMID21380710.S2CID8045294.
^Emerson, Thomas E.; Hedman, Kristin M.; Simon, Mary L. (2005). "Marginal Horticulturalists or Maize Agriculturalists? Archaeobotanical, Paleopathological, and Isotopic Evidence Relating to Langford Tradition Maize Consumption".Midcontinental Journal of Archaeology.30 (1):67–118.doi:10.1179/mca.2005.003.JSTOR20708222.S2CID129150225.
^Figure 21: World production of primary crops, main commodities (Report). United Nations, Food and Agriculture Organization, Statistics Division (FAOSTAT). November 29, 2023.doi:10.4060/cc8166en-fig21.
^Thakur, J. N.; Rawat, U. S.; Pawar, A. D. (1987). "First Record of Armyworm,Mythimna separata (Haworth) as a serious pest of maize in Kullu (HP) India and recommendations for its integrated management".Tropical Pest Management.33 (2):173–175.doi:10.1080/09670878709371141.
^Hermann, Hofbauer; Reinhard, R.; Klaus, Bosch; Reinhard, K.; Christian, Aichernig (January 2002)."Biomass CHP plant Güssing - A success story". Ministry of Economy and Labour and of the Federal States of Niederösterreich and Burgenland.S2CID56073239.
^Bassie, Karen (2002). "Corn Deities and the Complementary Male/Female Principle". In Lowell S. Gustafson; Amelia N. Trevelyan (eds.).Ancient Maya Gender Identity and Relations. Westport, Conn. and London: Bergin&Garvey. pp. 169–190.Archived from the original on July 10, 2009. RetrievedDecember 5, 2007.
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